package y23.Oct;

import java.util.Scanner;

public class Test11 {
    public static double f1(double x){
        return 2 * Math.pow(x,7) + 2 * Math.pow(x,5) + 4 * Math.pow(x,4)+80;
    }

    public static void main(String[] args) {
        double a = 0.0;
        double b = 0.0;
        double x = 0.0;
        Scanner scanner = new Scanner(System.in);
        a = scanner.nextDouble();
        b = scanner.nextDouble();
        while(true){
            if(f1(a) * f1(b) <= 0){
                break;
            }
        }
        while (Math.abs(a-b) > 0.0000001){
            x = (a + b) / 2;
            if (f1(a) * f1(x) <= 0) {
                b = x;
            }
            else {
                a = x;
            }
        }
        System.out.println((b + a) / 2);
    }
}
